Door made of plastic material for motor vehicles

ABSTRACT

There is provided a door for motor vehicles formed of plastic material, the parts of which are substantially manufactured by injection molding. The door consists of a center single piece support construction for transmitting forces to the frame of the motor vehicle body, an outer door shell secured on the support construction and an inner door shell. The support construction is formed by a profiled frame provided with stiffening elements extending throughout the door and a reinforcement arranged beneath the window opening. The profiled frame is a steplessly changing profile having stiffening elements formed by injected stiffening ribs, and the reinforcement arranged beneath the window opening is injected in the profiled frame and consists of horizontally extending load profiles and vertically extending ribs forming a lattice construction.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a door made of plastic material for motorvehicles, with a stiffening suitable for receiving the outer and innershells of the door, said stiffening transmitting the forces occurringinto the frame of the body of the vehicle.

2. Description of the Prior Art

Indisputably, the side door is a highly complicated component of thebody of a motor vehicle. The door has to have exceptionally highstrength and is expected to function even after a collision accident.

Generally, a door made of steel sheet satisfies said requirements.Efforts made to reduce the weight have resulted in door designscomprising a plastic outer shell of the door and a plastic inner shellof the door applied to a stiffening construction consisting of steelprofiles or sections. The forces acting on such a construction aretransmitted into the frame of the auto body by the stiffeningconstruction consisting of steel sections. With a known design, theouter and inner shells are manufactured by deep-drawing and combinedwith each other.

Said doors represent a combination of different materials; however, suchdoors do not meet the requirements in automobile constructionparticularly with respect to safety.

Now, the present invention is based on the problem of further reducingthe weight of a plastic door for motor vehicles and to construct such adoor in such a way that it will fully satisfy all requirements without astiffening construction made of steel sections while still havingsubstantial safety reserves.

SUMMARY OF THE INVENTION

According to the invention, said problem is solved in that thestiffening designed as a supporting construction, the outer shell of thedoor and the inner shell of the door are formed by prefabricated plasticparts capable of being joined together and produced mainly by injectionmolding, whereby the supporting construction may be formed by a profiledframe extending all around and having a reinforcement injection-moldedbeneath the window opening. Advantageously, the reinforcement injectedin the profiled frame is formed by horizontally extending load profilesand vertically extending ribs in the form of a latticework construction.Said load profiles may have any desired shape; however, advantageously,they have the shape of a "V", double "T" or "I" beam, or "U".

Said design provides a frame construction with torsional rigidity. Theload profiles permit the transmission of forces between the hinges andthe zone of the locking mechanism.

In accidents, the load profiles are kept in their horizontal position bythe vertically extending ribs. The latticework formed by thehorizontally extending load profiles and vertically extending ribsrepresents a safety cell by which forces occurring in accidents aretransmitted into the metal frame of the body of the vehicle.

According to another feature of the invention, the profiled frame has across section with the shape of a double "T" or "U". Stiffening ribsextending parallel to the flanges are injected on both sides of thecrosspiece of the double T-shaped profiled frame and on the crosspieceof the U-shaped profiled frame. Said stiffening ribs serve primarily forstiffening the profiled frame.

According to another feature of the invention, the outer shell of thedoor has an areal stiffening disposed on the inside of the shell,usefully, said stiffening has an asymmetric star shape with differentwall thicknesses. Advantageously, the outer side of the window pane isdisposed approximately on one plane with the window facing and outershell of the door. In this way, a low drag value is achieved within thezone of the window of the door and wind noise is largely avoided.

The invention provides a fully plastic door for motor vehicles that isproduced mainly by injection molding. Said door offers a significantweight reduction and it meets or largely exceeds the safety requirementsgiven for such doors. By using a high-quality plastic door made byinjection molding it is possible for the first time in auto bodyconstruction for the auto industry to construct the passenger cell as agenuine safety cell also as far as the sides are concerned. A staticflexural load of 3,000 kg is the requirement and standard with respectto the strength values of current door constructions made of auto bodysheet.

The plastic door with the design of the invention, which is manufacturedprimarily by injection molding from high-quality thermoplastics, iscapable of withstanding a static flexural load in the range of 6,000 and9,000 kg depending on the dimensions of the load profiles. This meansthat said plastic door assures a lateral construction of the passengercell with high torsional rigidity. Thus a notable gain in safety isobtained as compared to conventional door constructions particularly indangerous rear-and-front-end collisions. However, even other plasticssuch as, for example, duroplastics or elastomers may be used partiallyfor manufacturing the door, especially for producing the shells.

With the plastic door, stresses or loads are transmitted in two stages:in minor accidents, the transmission of such stresses takes placebetween the hinges and the lock mechanism. In major accidents, theprofiled frame of the door-supporting construction is additionallyforced into the metal frame of the vehicle skeleton without impairingthe function of the door, which is very important in view of the factthat it must always be possible to open the door. Embodiments of theinvention are shown in the drawing and explained in greater detailhereinafter.

BRIEF DESCRIPTION OF THE DRAWING

In the drawing,

FIG. 1 shows a perspective view of a profiled frame with a latticeworkconstruction injection-molded therein, an outer shell of the door and aninner shell of the door partially shown in a sectional view prior to theassembly of said parts;

FIG. 2 is a perspective view of a variation of a profiled frame with alatticework construction injection-molded therein;

FIG. 3a is a sectional view of a T-shaped profiled frame within the zoneof the window with a connected window facing including the window pane,as well as a glued-in window sealing strip;

FIG. 3b shows the same parts as FIG. 3a, but with a cut view within thezone of the window pane well;

FIG. 3c shows the same as FIG. 3a, but with a cut through the bottomzone;

FIG. 4a is a sectional view of a U-shaped profiled frame within the zoneof the window, with a connected window facing including the window paneand a glued-in door sealing strip;

FIG. 4b shows the same parts as FIG. 4a, but with a section through thezone of the window pane well;

FIG. 4c shows the same as FIG. 4a, but with a cut through the bottomzone;

FIGS. 5a to 5c are sectional views of a variation based on FIGS. 3a to3c;

FIGS. 6a to 6c show sectional views of a variation based on FIGS. 4a to4c;

FIG. 7 is a perspective view of a variation based on FIG. 4a, with anespecially large connection area between the window facing and profiledframe;

FIG. 8 is a perspective view of a variation based on FIG. 4a with a doorfacing on the profiled frame;

FIG. 9 is a perspective view of a lower main part of the supportingconstruction;

FIG. 10 shows a variation based on FIG. 4b with a separate plasticwindow frame;

FIG. 11 is a variation based on FIG. 4b with a separate metal windowframe;

FIG. 12 shows a variation based on FIG. 4b, with a metal window framerepresenting another variation of 4b; and

FIG. 13 shows a variation based on FIG. 4a for a door without a windowframe.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows that a reinforcement 2 in the form of a latticeworkconstruction is molded by injection in a profiled frame 1 having a crosssection with the shape of double "T" and extending all around. Saidreinforcement is formed by the horizontally extending load profiles 2'and the vertically extending ribs 2". Said load profiles 2' may have anydesired shape. In FIG. 1, the load profiles 2' have a V-shaped section,and FIG. 2 shows load profiles with a cross section in the shape of adouble "T" or "I" beam. The profiled frame 1 provides a frameconstruction with torsional rigidity forming with the reinforcment 2 thesupporting construction of the door, which door is to be viewed as adoor and safety cell. For enhancing the rigidity, the double "T" or "I"beam-shaped profiled frame 1 has the stiffening ribs 5 extendingparallel to the flanges. Said ribs are injection-molded on both sides ofthe crosspiece and arranged with a uniform spacing between each other.

The outer side of the latticework construction 2' and 2" is recessed forguiding the window pane 11. The vertical ribs 2", below the zone of thewindow pane, extend down to the inner surface of the outer shell 3 ofthe door. For guiding the window pane 11 laterally, the guide strips 12are arranged on the outwardly facing side of the latticeworkconstruction 2' and 2". Said strips 12 are made of plastic, too, andsecured by glueing. According to FIG. 1, the outer shell 3 of the dooris formed by a window facing 14, said facing having a Z-shaped crosssection and being divided in the horizontal direction. An arealstiffening 16 having the asymmetric shape of a star is disposed on theinner side of the outer door facing 3', said stiffening 16 havingdifferent wall thicknesses. On the inner side, the latticeworkconstruction 2' and 2" projects beyond the profiled frame. The innerlegs 7 of said profiled frame are extended horizontally and verticallyin the lower part of the supporting construction 1+2, forming a frame 8on the inner side. Also, on the inner side, the latticework construction2' and 2" and the profiled frame 1 may extend flush. Within the bottomzone, the frame 8 has the inwardly stepped steps 9.

The inner door facing 4 has a shaped cushion with a large rebound areawhich, in accidents, acts as an impact-reducing element. Said effect isincreased by rubber buffers disposed between the rib constructions ofthe inner shell 4 of the door and the supporting construction 1 +2. Thearm rest 27 is integrated in the inner door facing 4. The lock, handleand crank parts are arranged recessed for reasons of reducing the hazardof injury. If they are not arranged recessed, said parts are providedwith an adequate rebound area. The inner shell 4 of the door is usefullycovered with a textile material.

The supporting construction formed by the profiled frame 1 and thereinforcement 2, the latter in turn being formed by the load profiles 2'and the vertical ribs 2" forming a latticework construction, can beprefabricated. Said supporting construction and the outer shell 3 andthe inner shell 4 of the door are manufactured by injection molding fromhigh-quality modified thermoplastics. In terms of molding technology,the injection molding process offers nearly unlimited shapingpossibilities, so that any type of shape can be produced per se. Thepositions for installing the hinges, locks, centering devices andmirrors are injection-molded ready for the installation of said parts ifpossible in terms of molding techniques.

FIGS. 3a to 3c show a window facing 14 and an outer shell 3 arranged ondifferent sectional panels on a T or "I" beam-shaped profiled frame 1.Within the zone of the window, the window facing 14, which has aZ-shaped section in said zone, accommodates a guide strip 12 having anangularly shaped section. Within the zone of the window pane well, theplastic guide strip 12 has a U-shaped section, and the outer door shellfacing 3' has a plane profile 15 extending all around on the side facingthe supporting construction 1+2. The outer door shell facing 3' iscombined with the profiled frame 1 via said profile 15 by glueing orfusing. Said plane profile 15 is reinforced within the zone ofconnection. A door sealing strip 6 is glued into the inside of theprofiled frame 1, extending all around and abutting the stiffening ribs5 in a butt-joined connection. It is known that a decorative strip 29 isarranged on the window facing 14.

The FIGS. 4a to 4c show another variation of the sectional shape of theprofiled frame 1 with the matching arrangement of a window facing 14 andan outer door facing 3'.

In this case also, stiffening ribs 5 are arranged in the U-shapedprofiled frame 1. Instead of the guide strips 12 (plastic strips) shownin FIGS. 3 to 8 for laterally guiding the window pane 11, a U-shapedmetal profile may be arranged for guiding the window pane.

With the variation shown in FIG. 9, a lower main part 17 of thesupporting construction 1+2 is shown, said part being associated withthe part containing the zone of the window. On the top outermostlimitation of the main door part 17, a clearance 18 is provided in eachcase for receiving a window frame forming the part containing the zoneof the window. Said window frame may be made of plastic material 19 ormetal 19'. The connection between the window frame 19 or 19' and theplastic main door part 17 may be established in any desired way,advantageously by means of screwing the parts together.

The plastic window frame 19 has a supporting profile 20 and a profile 21for guiding the window pane, said profile 21 having the shape of a "U"and being glued into the supporting profile 20.

The metal window frame 19', according to FIG. 11, consists of asupporting profile 20' and a profile 21' for guiding the window pane,with said supporting profile 20' being covered by a plastic coverprofile 22 extending all around.

Within the zone of the window and in the window well, the window panemay be guided by a common metal frame 23. For said purpose, the metalframe 23 has a U-shaped section in the zone of the window and additionalinstallation legs 24 provided in the well of the window, said legs beingscrewed on the installation or mounting ribs 13 of the profiled frame 1.

According to FIG. 13, the door is designed frameless within the zone ofthe window. In this case, the window pane is guided on a plastic guidingprofile 25 embedded in the frame of the door, as well as on awindow-sealing strip 26 glued into the guiding profile 25.

The storage compartment 28 consists of plastic material and is usefullyglued into the inner shell 4 of the door. FIG. 1 shows that all requiredinstallation positions 10 are arranged in the inner shell 4 of the outerfacing 3' of the door and in the supporting constructions 1+2. Thehorizontal load profiles 2' and the vertically extending ribs 2" havereinforced and rounded ties provided on their joints and points ofconnection.

The plastic door according to the invention may be used for all types ofmotor vehicle, including its use as a hatch-type door.

In the present case, the door represents a typical group of componentsmanufactured from high-quality chemical materials. By combiningdifferent chemical materials which are each selected for their specificproperties, a light-weight door for auto bodies is provided which meetsthe most exacting safety requirements.

For the load part, i.e. the supporting construction, it is possible toselect, for example, a modified thermoplastic material such as amodified type of polyamide 6 with or without filler. Especially highstrength combined with high rigidity is required for the profiled loadpart, among other properties.

A mineral-filled duroplastic material or a modified thermoplastic in theform of a modified polybutylene teraphthalate (PBTP) with high impactstrength is suitable, among other materials, for the outer shell of thedoor. In particular rigidity and good optical surface quality arerequired for said part

A thermoplastic material such as, for example, polypropylene, or aPUR-material is suitable for the inner shell of the door. As a lining,said component has to assume also functions of interior or passivesafety.

The development of highly valuable chemical materials is still underway. In plastic research, work is being performed especially for thedevelopment of "custom-made" polymer materials, which are noted for highmechanical and thermal stressability, special optical properties, theirself-reinforcing nature (liquid crystals), and excellent resistance tochemicals, etc. Polymer blends with an attractive price-performanceratio will be available in the medium-term future and open up a newmarket on the body-building sector of the automobile industry.

Technological progress, cost optimization combined with superiorquality, improvements of the manufacturing process for facilitating theproduction operation and reduction of the production cost are therequirements to be satisfied for the mass production of light-weightbody parts made from chemical materials.

Stubbe, by developing a series of manufacturing machines for the massproduction of auto body parts, has created a new technology for theconstruction of auto body parts from chemical materials that is meetingsaid requirements.

What is claimed is:
 1. A motor vehicle door formed of plastic materialwhose parts are substantially manufactured by injection molding, saiddoor consisting of a center single-piece support construction fortransmitting forces to the frame of the body of the motor vehicle, anouter door shell and an inner door shell secured on said supportconstruction, the support construction being formed of an outer profiledframe extending around the periphery of said door and being providedwith stiffening elements and a reinforcement arranged beneath the windowopening, the improvement comprising: said profiled frame having asteplessly changing profile cross section along the door periphery, thestiffening elements of said profiled frame being formed by injectionmolded stiffening ribs, and the reinforcement arranged beneath thewindow opening being injection molded in the profiled frame andconsisting of horizontally extending load profiles and verticallyextending ribs forming a lattice construction extending throughout thedoor beneath the window opening.
 2. The door for motor vehicles asdefined in claim 1, wherein the cross-section of the profiled frame hasa "U" shape.
 3. The door for motor vehicles as defined in claim 1,wherein the load profiles have a "U" shape.
 4. The door for motorvehicles as defined in claim 1, wherein the load profiles have an "I"beam shape.
 5. The door for motor vehicles as defined in claim 1,wherein the cross section of the profiled frame has an "I" beam shape.6. The door for motor vehicles as defined in claim 1, wherein thestiffening ribs are arranged with equal spacing therebetween along saidprofiled frame.
 7. The door for motor vehicles as defined in claim 1,wherein a door sealing strip is inserted in the profiled frame on aninner side of the door.
 8. The door for motor vehicles as defined inclaim 7, wherein the door sealing strip is secured by glueing,butt-joining the stiffening ribs.
 9. The door for motor vehicles asdefined in claim 1, wherein the load profiles have the shape of a "V".10. The door for motor vehicles as defined in claim 1, wherein a lowerzone of the door between the profiled frame and the lowermost,horizontally extending load profile, the vertical ribs extend directlyup to the inner surfaces of the outer shell of the door.
 11. The doorfor motor vehicles as defined in claim 1, wherein the horizontal loadprofiles and the vertically extending ribs project beyond the profiledframe at an inwardly facing side of the support construction.
 12. Thedoor for motor vehicles as defined in claim 1, which further comprisesinner legs extending horizontally and vertically from said profiledframe in said door beneath said window opening so as to form a frameextending from an inside surface of said door.
 13. The door for motorvehicles as defined in claim 12, wherein said frame extending from theinside surface of said door is stepped at the door bottom.
 14. The doorfor motor vehicles as defined in claim 12, wherein said frame extendingfrom the inside surface of said door is aligned flush with thehorizontal load profiles and the vertically extending ribs.
 15. The doorfor motor vehicles as defined in claim 1, wherein said profiled frameextends flush with the lattice construction of horizontally extendingload profiles and vertically extending ribs.
 16. The door for motorvehicles as defined in claim 1, wherein an outer side of the latticeconstruction of horizontally extending load profiled and verticallyextending ribs is recesed for guiding a window pane.
 17. The door formotor vehicles as defined in claim 1, wherein said outer shell of thedoor is formed by a window facing extending around the window openingand an outer door panel arranged beneath the window opening.
 18. Thedoor for motor vehicles as defined in claim 17, wherein the windowfacing has a Z-shaped cross section.
 19. The door for motor vehicles asdefined in claim 17, wherein the window facing is injection-molded onthe profiled frame.
 20. The door for motor vehicles as defined in claim17, wherein a window pane is disposed substantially on the same planewith the window facing and the outer shell of the door.
 21. The door formotor vehicles as defined in claim 17, wherein the outer panel of thedoor has a plane profile extending therearound on the side facing thesupporting construction, said profile resting against the profiled frameand being connectable thereto.
 22. The door for motor vehicles asdefined in claim 21, wherein said plane profile of the outer panel ofthe door is reinforced in the zone of connection with the profiledframe.
 23. The door for motor vehicles as defined in claim 21, whereinthe plane profile of the outer shell of the door, said profile restingagainst the profiled frame, is connected with said frame by glueing orfusing.
 24. The door for motor vehicles as defined in claim 21, whereinsaid outer door panel has an areal stiffening on an inside surfacethereof.
 25. The door for motor vehicles as defined in claim 24, whereinthe areal stiffening has an asymmetric shape of a star.
 26. The door formotor vehicles as defined in claim 24, wherein the areal stiffening hasdifferent wall thicknesses.
 27. The door for motor vehicles as definedin claim 24, wherein the areal stiffening decreases steplessly from acenter thereof outwardly.
 28. The door for motor vehicles as defined inclaim 1, wherein the support construction is formed by a lower partcovering the main part of the door, and a part covering the window areaof the door.
 29. The door for motor vehicles as defined in claim 28,wherein on a topmost limitation of the main part of the supportconstruction, a recess or clearance is provided for receiving a frameforming the window part of the door.
 30. The door for motor vehicles asdefined in claim 28, wherein the door is designed frameless within thearea of the window, and a window pane is guided on a guiding profilemade of plastic material and a window-sealing strip.
 31. The door formotor vehicles as defined in claim 30, wherein the guiding profile isembedded in the frame of the door.
 32. The door for motor vehicles asdefined in claim 30, wherein the window-sealing strip is glued into theguiding profile.
 33. The door for motor vehicles as defined in claim 1,wherein on a side of the inner shell of the door facing the supportconstruction, the inner shell has an angle profile extendingtherearound, said profile resting against the profiled frame and beingconnectable thereto.
 34. The door for motor vehicles as defined in claim33, wherein the angle profile of the inner shell of the door isreinforced within the zone of connection to the profiled frame.